Pre-Treatment with Reserpine Does Not Shorten the Duration of N-Methyl-N'-Nitro-N-Nitrosoguanidine (MNNG)-Induced Stomach Adenocarcinoma in Female Sprague-Dawley Rats

摘要

Background: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is often used to induce adenocarcinoma in the stomach of rats; taking about 40 weeks to develop. It is however less effective in female rats and it is unknown if its effectiveness could be improved and its duration shortened by pre-treatment with reserpine, an agent used to induce peptic ulceration. Objective: This study therefore examined the effects of MNNG-induced tumorigenesis in female Sprague-Dawley rats pre-treated with a single dose of reserpine. Design/Materials and Methods: Forty-eight, 6-week old female rats were divided into six groups. Group A, normal control euthanized at day 0; Group B, euthanized 24 hours after reserpine treatment; Groups D and F were treated with reserpine and MNNG and then euthanized at 20 and 40 weeks respectively; Groups C and E were treated with reserpine and acted as age-matched controls for groups D and F respectively. A stat intraperitoneal injection of 20 mg/kg of reserpine was given followed by daily administration of MNNG at a dose of 10 mg/kg/day in drinking water. Body weight and water intake were measured weekly throughout the study, and the data were analysed using 2-way ANOVA. Following euthanization, their stomachs were collected for histo-pathological examination. Results: There was no difference in body weight and water intake between the two groups. Stomachs of rats exposed to reserpine and MNNG for 40 weeks showed no evidence of tumour formation. Conclusion: Pre-treatment with reserpine to induce acute ulceration in the stomach of Sprague-Dawley rats did not result in the development of MNNG-induced stomach adenocarcinoma.